Circuit breaker



H. D. DORFMAN CIRCUIT BREAKER June 21, 1960 2 Sheets-Sheet 1 Filed May26, 1958 INVENTOR Hiller D. Dorfmun WITNESSES ATTORNEY June 21, 1960 H.0. DORFMAN CIRCUIT BREAKER Fig.

Fig.4.

United States Patent @fifice Patented June 21, 1960 CIRCUIT BREAKERHiller D. Dorfman, Beaver, Pa., assignor to Westinghouse ElectricCorporation, East Pittsburgh, Pa., a corporation of Pennsylvania FiledMay 26, 1958, Ser. No. 737,600

8 Claims. (Cl. 200-106) of the circuit breaker without removing thebreaker cover.

Another object of the invention is to provide a circuit breakerembodying an electromagnetic tripping means comprising a fixed magnetyoke and a movable armature with improved means for adjusting oneelement of said electromagnetic tripping means to vary the magnetic airgap to thereby vary the minimum overload current required to trip thebreaker.

Another object of the invention is to provide a circuit breakerembodying a tripping electromagnet hawing a fixed magnet yoke and amovable armature with improved means occupying a minimum of space foradjusting the position of the armature relative to the fixed magnet yoketo vary the tripping characteristic of the tripping electromagnet.

The invention both as to structure and operation, together withadditional objects and advantages thereof, will be best understood fromthe following detailed description thereof when read in conjunction withthe accompanying drawings.

In said drawings:

Figure l is a vertical sectional view through a circuit breakerembodying the principles of the invention.

Fig. 2 is a top plan view of a portion of the circuit breaker with thecover broken away showing a portion of the adjusting means for one poleof the breaker.

Fig. 3 is an enlarged elevational view partly in section showing theadjusting means.

Fig. 4 is an enlarged elevational view of the adjusting cam.

The invention is illustrated as applied to a circuit breaker embodyingan operating and contact mechanism of the type fully disclosed in PatentNo. 2,419,125, issued Apr. 15, 1947, to Hiller D. Dorfman and Gerald J.Freese and assigned to the assignee of the present invention.

The circuit breaker is of the two or three-pole type and, since thecontact and trip means for all poles are the same, only the center polein which the operating mechanism is located will be described. Thecircuit breaker comprises generally a base 11 and a cover 13 both ofmolded insulating material, a stationary contact 15, a movable contact17, an operating mechanism indicated generally at 19 and a trip deviceindicated generally at 21.

The stationary contact 15 is rigidly mounted on the inner end of aconducting strip 23 which has a terminal connection 25 at its outer end.The movable contact 17 is mounted on a movable switch arm 27 which ispivoted at 29. The operating mechanism 19 consists of a releasablemember 31 pivoted at 33 and operatively connected to the switch arm 27by a pair of toggle links 35 and 37. The knee of the toggle 3537 isconnected by means of over-center operating springs 39 to a pivotedoperating handle 41 which is movable between an on and an off positionto effect movement of the switch arm 27 to the closed and open positionsin a Well known manner.

When the circuit breaker is in the closed position, the toggle 35-37 isin an overset position and holds the switch arm 27 in the closed contactposition. When the circuit breaker is in the closed position and thereleasable member 31 is released, it causes collapse of the toggle 35-37and movement of the switch arm to the open position. The mechanism isreset and relatched by movement of the operating handle 41 to the offposition. Thereafter, the contacts are closed by movement of the handle41 to the on position.

Only a brief description of the operating mechanism and its operationhas been given. For a fuller understanding of the operating mechanism,reference may be had to the previously mentioned Patent No. 2,419,125.

The releasable member 31 is releasably held in its operative position byengagement of the free end thereotwith a latch 43 mounted on a pivotedtrip bar 45 that is common to all of the poles of the breaker and whichis operated by the trip device 21 of any pole of the breaker to elfectrelease of the releasable member 31.

The trip device 21 comprises an electromagnet indicated generally at'47comprising a fixed angular magnet yoke 51 of magnetic material having afixed core 53 rigidly secured thereto about which is Wound an energizingcoil 55. The upper end of the fixed core 53 forms a pole piece 56. Thelower end of the coil 55 is connected to a terminal 57 which is securedto the base 11 by a screw 59. A flexible conductor 61 is connected, atone end, to the terminal 57 and, at the other end, to the movablecontact member 17. The upper end of the coil 55 is rigidly secured tothe inner end of a conductor 63 at the outer end of which is mounted aterminal connector 65.

Mounted on the upwardly extending portion of the yoke 51 is a bracket 67of non-magnetic material having an opening therein in which is pivotallysupported an armature 69 which is provided with a projection 71. Theprojection 71 extends downwardly and has an insulating member 75 on thelower end thereof which, upon operation of the armature 69, engages aprojection 77 on the trip bar 45 and actuates the latter to effectrelease of the releasable member 31. The armature 69 is biased to itsunattracted position by springs 79 tensioned between the bracket 67 anda bracket 81 of magnetic material secured to the armature 69.

The electromagnet 47 is supported by means of projections 83 on oppositesides of the angular yoke 51 which extend through openings in spacedside plates 85 which form a frame. The side plates 85 are provided withprojections 87 at their lower ends which extend through openings in thebase 11 and are riveted over at 89 to rigidly secure the frame and thetrip unit to the base.

Means is provided to selectively determine the minimum overload currentrequired to trip the breaker. This is accomplished by adjusting theposition of the armature by means of an adjusting device shown generallyat 91. The adjusting device is supported by a plate 93 (Fig. 3) rigidlysecured to the side plates 85. Mounted for rotation relative to theplate 93 is an adjusting knob 95 which extends through an opening in thecover 13. A spring Washer 97 biases a flange 99, Which is integral withthe knob 95, against the inner surface of the cover 13. A reducedportion 101 of the knob 95 rotates in:

- an opening in the plate 93 and has a downwardlyexq;

3 tending shaft 103 at the lower end thereof. A cam 195 is mounted onthe non-circular portion of shaft 103 (shown in Fig. 2) for rotationtherewith and is held in ,placeby a springclip 1G7 seated in a groove 1lin the shaft. Apin or plungerof non-magnetic material 111 is disposedbetween the-cam 165 and a struckout portion 113 of the armature 69. Arounded head-115 of the pin 111 bears against the underside of the cam105 and the lower end of the pin serves as a stop for the armature 69.As seen in Fig. 4, the under surface of the cam 1105 is stepped asindicated at117 so that, upon rotation of the cam,.thepin or stop 111 ismoved up or down depending on the directionof rotation. This movement ofthe pin 111, through the portion 113 on the armature .69, varies theposition of the armature relative to the pole piece 56 and the size ofthe air gap there'cetween.

The pin or stop 111 is guided by a sleeve 1-19 of nonmagnetic materialwhich surrounds the pin and is rigidly mounted in an adjustable guideplate 121. The guide plate 121 also of non-magnetic material ispivotally supported at one end by trunnions 12 3 thereon which extendinto bearing openings 125 in the side plates or frame 85. A screw 127which threadedly engages the plate 121 at its end opposite thetrunnions, has a reduced portion 129 which fits in a narrow slot 131 inthe fixed plate 93 and a head 133 bearing against the upper surface ofthe plate 93. The slot 131 is of less width than the body or the screw127, so that upon turning the screw 127, it is held against endwisemovement and the guide plate .121 is moved up or down about its pivot123 thereby .changing the angle of the pin 111 with respect to theportion 113'. It will be seen that this movement will also vary thepoint of engagement of the lower end of the pin 111 with the portion 113there-by varying the moment arm of the pin relative to the pivot of thearmature '69. This arrangement provides a. fine adjustment for thefactory calibration of the device and this calibration may be fixed bysolder 134 or other sealing material.

Further factory calibration may be eiiected by bending the portion 113of the cracket 81 which is secured to the armature 69. This varies theposition or" the armature 69 relative to the pin 111 and thereby variesthe magnetic air gap.

. In calibrating the. trip device, the knob 95 (Figs. 2 and 3), is firstrotated to the H? position after which the portion 113 is bent up ordown to provide the correct air gap for the Hi setting. The knob 95 isthen rotated tothe Lo position and the screw 127 is then rotated in thedirection to give the correct air gap for the 1.0" setting.

The top of the knob 95 is provided with a pointer 135 (Fig.2) and thecover 13 is provided with index points 137, around the knob 95. Theupper surface of the cam 105 is provided with notches 1.39 (Fig. 4-)which correspond to the index positions 137. The notches 139 are adaptedto engage a projection 141 on the underside of the fixed plate 93 toprevent accidental movement of the knb'95 and the cam 1 35.

Adjustment of the armature 69 is eifected by inserting a screw driver inthe slot in the knob 65 and pushing the knob down to disengage the notch139 in the earn 105 from. the projection 1.41. The knob is then rotatedto bring the pointer 135 to the desired index point. This rotates thecam 195 to bring the selected step 117 into engagement with the head 115of the pin 111. When the knob and cam are in the selected position, theknob is released and the spring 97 restores the parts upwardly to engagethe selected notch 139 with the projection 14 1.

While the invention has been disclosed in accordance with the provisionsof the patent statutes, it is to be understood that various changes inthe structural details and arrangement of parts thereof may be madewithout cleparting from the spirit of the invention.

I claim as my invention:

1. A circuit breaker comprising relatively movable contact means andmeans releasable to effect opening of said contact means, trip meansincluding a trip member movable to a tripping position to effect releaseof said releasable means, electromagnet tripmeans having an armaturemovable to engage and move said trip member to said tripping position,a. settable member for varying the magnetic air gapof saidelectromagnetic means, an actuating memberdisposed between said settablemember and a portion on said armature, said actuating member engagingsaidportion on said armature and moved by said settable member to varythe position of said armature, and guide means to guide said actuatingmember for longitudinal movement.

2. A circuit breaker comprising relatively movable contact means andmeans releasable to efiect opening of said. contact means, trips meansincluding a trip member movable to a tripping position to eftect releaseof said releasable means, electromagnet trip means having an armaturemovable to engage and move said trip memher to said tripping position, asettable cam member for varying the magnetic air gap of saidelectromagnetic means, an actuating plunger disposed between saidsettable cam member and a portion on said armature and moved by saidsettable cam member to vary the position of said armature, andadjustable guide means for said actuating plunger adjustable to vary theangular position of said actuating plunger relative to said portiononsaid armature.

3. A circuit breaker having relatively movable contact means and meansreleasable to effect opening of said contact means, a trip membermovable to a tripping position to effect release of said releasablemeans, electromagnetic trip means including a fixed magnet yoke and anarmature movable to engage and move said trip member to said trippingposition, a slidable adjusting member having one end disposed inengagement with a portion on said armature, a manually settable cammember engaging the other end of said slidable member for actuating saidslidable member, guide means for said slidable member, and means foradjusting the position of said guide means to thereby vary the positionof said slidable member relative to said portion on said armature.

4. A circuit breaker having relatively, movable contact means and meansreleasable to effect opening of said con tact means, a trip membermovable to a tripping position to effect release of said releasablemeans, electromagnetic trip means including a fixed magnet yoke and anarmature movable to engage and move said trip member to said trippingposition, a slidable adjusting memher having one side disposed inengagement with a portion on said armature, a manually settable cammember engaging the other end of said slidable member for actuating saidslidable member, pivoted guide means for said slidable member, and meansfor adjusting the position of said guide means to thereby vary theangular position of said slidable member relative to said-portion .onsaid armature.

5. A circuit interrupting current responsive device comprising anenergizing winding, a fixedmagnet yoke including a fixed core memberdisposed to -be energized by said winding, a pivoted armature movabletoward and away from said fixed core member, a rotatable cam member,means for rotating said cam member, a slidable member disposed betweensaid cam member and said armature and slidably movable by rotation ofsaid cam member to vary the position of said armature relative to saidfixed core member, guide means for guiding the sliding movement of saidslidable member, and adjusting means adjustable to vary the position ofsaid glide-means to thereby vary the angular position of said slidablemember relative to said armature.

6. A circuit interrupting current responsive device comprisingtin-energizing winding, electromagnetic means comprising a fixed coremember disposed to be energized by said winding, a pivoted armaturemovable toward and away from said fixed core member, a frame supportingsaid electromagnetic means, adjusting means comprising a rotatable cammember supported on said frame independently of said electromagneticmeans, a slidable member disposed between said cam member and saidarmature and slidably movable by rotation of said cam member to vary theposition of said armature relative to said fixed core member, guidemeans pivotally mounted on said frame for guiding the sliding movementof said slidable member, and means for pivotally adjusting said guidemeans to thereby vary the angular position of said slidable memberrelative to said armature.

7. A circuit interrupting current responsive device comprising anenergizing Winding, a fixed core member disposed to be energized by saidwinding, a movable armature movable relative to said fixed core member,adjusting means comprising a slidable member having one end engagingsaid armature, rotatable cam means engaging the other end of saidslidable member, means for rotating said cam means to cause slidingmovement of said slidable member to vary the position of said armaturerelative to said fixed core member, guide means for said slidablemember, and means for adjusting said 6 guide means to vary the angularposition of said slidable member relative to said armature.

8. A circuit interrupting current responsive device comprising anenergizing Winding, a fixed core member disposed to be energized by saidwinding, a pivoted armature movable relative to said fixed core member,adjusting means comprising a slidable member having one end engagingsaid armature, rotatable cam means engaging the other end of saidslidable member, means for rotating said cam means to cause slidingmovement of said slidable member to vary the position of said armaturerelative to said fixed core member, pivoted guide means for saidslidable member, and means for adjusting said guide means about itspivot to vary the angular position of said slidable member relative tothe pivot of said armature.

References Cited in the file of this patent UNITED STATES PATENTS2,135,490 Blodgett Nov. 8, 1938 2,691,707 Lovejoy Oct. 12, 19542,824,925 Grissinger et a1. Feb. 25, 1958 FOREIGN PATENTS 218,702 GreatBritain July 7, 1924

